We are developing a lightweight Raman imager for detecting harzardous chemical compounds on surfaces in emergency settings such as industrial accidents, terrorist attacks, and chemical warfare. Our instrument is based on a compact Fourier-Transform hyperspectral sensor which records interferograms used as signatures of chemicals compounds. Two important challenges relating to the detection of small amounts of chemicals with our device are (i) crosstalk artefacts degrading the reproducibility of the measurements, and (ii) the mixture of signatures from target compound and substrate material. We report on advances on crosstalk correction, and chemical detection by linear unmixing of the signatures. The system is demonstrated on the detection of two organophosphorus compounds on PMMA, a polymer with mild Raman signal.
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